Implemented: Enablement of bid energy MaxAvail for semi-scheduled generators

Use of bid MaxAvail implemented

Today, August 7, 2023,  we were notified that the change to NEMDE that supports MaxAvail in the Bid for Semi-Scheduled generators,  highlighted a week earlier in this update, has happened.

This means the MaxAvail field in energy bids for semi-scheduled units will now act as a cap on dispatch availability. The email  received just after 4pm, included the following description:

AEMO wishes to advise, as of 13:40 (AEST) today, it has successfully implemented bid Max Avail in the Production environment under CHG0079740. The bid Max Avail is now applied to all NEMDE and PASA processes, and is being reflected in relevant NEM Reports outlined in the attached change notice (see EMMS Technical Specification Data Model v5.2 release for detailed changes to reports).

It provides a way for units to change their availability to a level lower than what the unconstrained intermittent generation forecast would produce.

At the unit-level, and in aggregate at region-level, we expect to see the impact of this show up as a difference between the semi-scheduled unconstrained intermittent generation forecast (UIGF) and availability (when the bid MaxAvail is lower).

We’ll be keeping an eye on how this is used as time progresses over the coming days.

Having overcome some hurdles

Initially,  in May, the change was anticipated to be implemented by mid-June. However, extensions to the timetable were necessary.

  • On 2 June, a delay due to user acceptance testing required a reschedule to late-June.
  • On 19 June, due to scheduling dependencies and risk management a tentative date was set for 12 July.
  • On 11 July, were were notified a that performance risk in the Pre-Production environment had been identified (reported here) and to minimise any risk in Production, the implementation was to be again rescheduled.
  • On 1 August confirmation was circulated that the change would be implemented on 7 August, having rectified the performance risk identified in July.
  • Today, 7 August, the change has been implemented.

Handy Links

The email notification of the change also included links to these updated procedures and documents:



About the Author

Linton Corbet
Linton joined Global-Roam as a software engineer and market analyst in August 2020. Prior to joining us, he worked with the AEMO for 7 years, and before that, as an air quality scientist.

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